CN102683612A - Light emitting device, illumination apparatus and display apparatus - Google Patents

Abstract

The invention discloses a light emitting device, lighting equipment and display equipment. The light emitting device includes: an organic layer sandwiched between a first electrode and a second electrode to serve as an organic layer including a light emitting layer emitting monochromatic light at one position; a first light reflection interface disposed near the first One side of the electrode is used as an interface that reflects light emitted from the light-emitting layer so that the reflected light is emitted from a side close to the second electrode; and a second light reflection interface, a third light reflection interface, and a fourth light reflection interface Interfaces are sequentially arranged at positions separated from each other in a direction from the first electrode to the second electrode on a side close to the second electrode.

Description

Light emitting device, lighting device and display device

technical field

The present invention relates to a light emitting device, a lighting device using the light emitting device, and a display device using the light emitting device. More specifically, the present technology relates to a light emitting device using electroluminescence of an organic material, a lighting device using the light emitting device, and a display device using the light emitting device.

Background technique

As a light-emitting device capable of emitting light with high luminance when driven at a low DC (direct current) voltage, a light-emitting device using electroluminescence of an organic material has attracted much attention, and such light-emitting devices have been extensively and intensively studied. In the following description, a light emitting device using electroluminescence of an organic material is referred to as an organic EL device. An organic EL device has a structure in which an organic layer is sandwiched between a light reflective electrode and a light transmissive electrode. The organic layer includes a light-emitting layer with a thickness typically between tens of nanometers and hundreds of nanometers. Light emitted from a light-emitting layer of such an organic EL device undergoes interference within the device structure before being picked up by an external device. In the past, attempts have been made to improve the luminous efficiency of organic EL devices by utilizing such interference.

Japanese Patent Laid-Open No. 2002-289358 discloses a technique. According to this technology, by setting the distance from the emission position to the light reflection layer as the distance at which light having the emission wavelength resonates, the light emitted from the light emission layer toward the light transmissive electrode and the direction from the light emission layer toward the light reflection electrode are utilized. Interference of emitted light to improve luminous efficiency. In this way, luminous efficiency can be improved.

According to the technique disclosed in Japanese Patent Laid-Open No. 2000-243573, light reflection at the interface between the light-transmitting electrode and the substrate is considered in predetermined two distances. These two distances are the distance from the light-emitting position to the light-reflecting electrode and the distance from the light-emitting position to the interface between the light-transmitting electrode and the substrate.

According to the technology disclosed in the pamphlet of PCT Patent Publication No. WO01/039554, by setting the thickness of the layer provided between the light-transmitting electrode and the light-reflecting electrode so that light having a desired wavelength resonates, the gap between the light-transmitting electrode and the light-reflecting electrode Interference caused by multiple light reflections between them is used to improve luminous efficiency.

According to the technology disclosed in Japanese Patent No. 3508741, as a technology for improving the viewing angle characteristics of a white chromaticity point (chromaticity point) in a display device (by combining a light emitting device structure each utilizing a resonator structure to increase luminous efficiency), it is proposed to adjust the A method of controlling the attenuation balance of the three colors (ie, R (red), G (green), and B (blue)) by the thickness of the organic layer.

However, according to the above technique, in an organic EL device that utilizes emitted light interference to increase luminous efficiency, if the wavelength band width of the interference filter of the acquired light h is narrowed, the viewing angle dependence of the luminous characteristics increases, due to the separation from the oblique direction. It is proved by the fact that the wavelength of light h shifts significantly when looking at the luminous surface, and the luminous intensity attenuates.

On the other hand, there is also a technique disclosed in Japanese Patent Laid-Open No. 2006-244713. According to this technology, the phase of light emitted by a light reflection layer of an organic light emitting device having a narrow-band monochromatic spectrum and interference caused by a single light reflection layer disposed on a light emitting side are set so as to produce inversion of a center wavelength. In this way, changes in hue caused by changes in viewing angle can be avoided. In this case, the number of light-emitting wavelengths and the number of light-reflecting interfaces of one device are limited to one, so that the brightness of monochromatic light and the viewing angle characteristics of monochromatic light can be maintained. However, there is not a wide enough band to eliminate hue variations. Furthermore, if one tries to broaden this band, one needs to enhance mutual cancellation by increasing the reflectivity. In this case, however, the efficiency is significantly attenuated.

Contents of the invention

In order to solve the above-mentioned problems, the present technology provides a light-emitting device capable of emitting light that can be well captured in a wide wavelength band and that can significantly reduce the viewing angle dependence of luminance and the viewing angle dependence of the hue of monochromatic light sex.

Furthermore, in order to solve other problems of the related art, the present technology also provides a lighting device that has little viewing angle dependence, has good light distribution characteristics, and is easily and efficiently manufactured.

In addition to this, in order to solve other problems of the related art, the present technology also provides a display device capable of displaying a high-quality image with little viewing angle dependence, and which can be manufactured with high efficiency.

In order to solve the above problems, the light emitting devices provided by the present technology include:

an organic layer sandwiched between the first electrode and the second electrode to serve as an organic layer including a light emitting layer emitting monochromatic light at one position;

a first light reflection interface provided on a side close to the first electrode to serve as an interface that reflects light emitted from the light emitting layer so that the reflected light is emitted from a side close to the second electrode; and

The second light reflection interface, the third light reflection interface and the fourth light reflection interface are sequentially arranged at positions separated from each other in a direction from the first electrode to the second electrode on the side close to the second electrode.

In this light emitting device,

Symbol L1 represents the optical distance between the first light reflection interface and the luminescent center of the luminescent layer;

Symbol L2 represents the optical distance between the luminescent center and the second light reflection interface;

Symbol L3 represents the optical distance between the luminescent center and the third light reflection interface;

Symbol L4 represents the optical distance between the luminescent center and the fourth light reflection interface;

The symbol λ1 represents the central wavelength of the emission spectrum of the light-emitting layer;

The symbols n, m, m' and m" each denote an integer;

The symbols λ11, λ12, λ13 and λ14 each denote an interference wavelength;

The length unit nanometer is used as the unit for the wavelengths λ1, λ11, λ12, λ13 and λ14;

表示当各波长的光被第一光反射界面反射时观察到的相位变化；symbol

Indicates the phase change observed when the light of each wavelength is reflected by the first light reflecting interface;

symbol Indicates the phase change observed when the light of each wavelength is reflected by the second light reflecting interface;

表示当各波长的光被第三光反射界面反射时观察到的相位变化；symbol

Represents the phase change observed when the light of each wavelength is reflected by the third light reflection interface;

表示当各波长的光被第四光反射界面反射时观察到的相位变化；symbol

Represents the phase change observed when the light of each wavelength is reflected by the fourth light reflection interface;

The optical distances L1, L2, L3, and L4 satisfy the expressions (1) to (8) given below:

n≥0时…(1)

When n≥0...(1)

λ1-150<λ11<λ1+80 ...(2)

λ1-80<λ12<λ1+80 ...(6)

λ1-150<λ13<λ1+150 ...(7)

λ1-150<λ14<λ1+150 ...(8)

In addition, the present technology also provides a lighting device employing a plurality of light emitting devices for emitting light having a plain color (monochromatic) different from each other, and each light emitting device includes:

an organic layer sandwiched between the first electrode and the second electrode to serve as an organic layer including a light-emitting layer that emits monochromatic light at one position;

a first light reflection interface disposed on a side close to the first electrode to serve as an interface that reflects light emitted from the light-emitting layer so that the reflected light is emitted from a side close to the second electrode; and

The second light reflection interface, the third light reflection interface and the fourth light reflection interface are sequentially arranged at positions separated from each other in the direction from the first electrode to the second electrode on the side close to the second electrode.

In this light emitting device,

Symbol L1 represents the optical distance between the first light reflection interface and the luminescent center of the luminescent layer;

Symbol L2 represents the optical distance between the luminescent center and the second light reflection interface;

Symbol L3 represents the optical distance between the luminescent center and the third light reflection interface;

Symbol L4 represents the optical distance between the luminescent center and the fourth light reflection interface;

The symbol λ1 represents the central wavelength of the emission spectrum of the light-emitting layer;

The symbols n, m, m' and m" each denote an integer;

The symbols λ11, λ12, λ13 and λ14 each denote an interference wavelength;

The length unit nanometer is used as the unit for the wavelengths λ1, λ11, λ12, λ13 and λ14;

symbol Indicates the phase change observed when the light of each wavelength is reflected by the first light reflecting interface;

表示当各波长的光被第二光反射界面反射时观察到的相位变化；symbol

Indicates the phase change observed when the light of each wavelength is reflected by the second light reflecting interface;

表示当各波长的光被第三光反射界面反射时观察到的相位变化；symbol

Represents the phase change observed when the light of each wavelength is reflected by the third light reflection interface;

表示当各波长的光被第四光反射界面反射时观察到的相位变化；symbol

Represents the phase change observed when the light of each wavelength is reflected by the fourth light reflection interface;

The optical distances L1, L2, L3, and L4 satisfy all of the expressions (1) to (8) given above.

In addition, the present technology also provides a display device employing a plurality of light emitting devices for emitting light having different plain colors from each other, and each light emitting device includes:

an organic layer sandwiched between the first electrode and the second electrode to serve as an organic layer including a light emitting layer emitting monochromatic light at one position;

a first light reflection interface provided on a side close to the first electrode to serve as an interface that reflects light emitted from the light-emitting layer so that the reflected light is emitted from a side close to the second electrode; and

The second light reflection interface, the third light reflection interface and the fourth light reflection interface are sequentially arranged at positions separated from each other in the direction from the first electrode to the second electrode on the side close to the second electrode.

In this light emitting device,

Symbol L1 represents the optical distance between the first light reflection interface and the luminescent center of the luminescent layer;

Symbol L2 represents the optical distance between the luminescent center and the second light reflection interface;

Symbol L3 represents the optical distance between the luminescent center and the third light reflection interface;

Symbol L4 represents the optical distance between the luminescent center and the fourth light reflection interface;

The symbol λ1 represents the central wavelength of the emission spectrum of the light-emitting layer;

The symbols n, m, m' and m" each denote an integer;

The symbols λ11, λ12, λ13 and λ14 each denote an interference wavelength;

The length unit nanometer is used as the unit for the wavelengths λ1, λ11, λ12, λ13 and λ14;

表示当各波长的光被第一光反射界面反射时观察到的相位变化；symbol

Indicates the phase change observed when the light of each wavelength is reflected by the first light reflecting interface;

表示当各波长的光被第二光反射界面反射时观察到的相位变化；symbol

Indicates the phase change observed when the light of each wavelength is reflected by the second light reflecting interface;

表示当各波长的光被第三光反射界面反射时观察到的相位变化；以及symbol

represents the phase change observed when light of each wavelength is reflected by the third light-reflecting interface; and

表示当各波长的光被第四光反射界面反射时观察到的相位变化；symbol

Represents the phase change observed when the light of each wavelength is reflected by the fourth light reflection interface;

The optical distances L1, L2, L3, and L4 satisfy all of the expressions (1) to (8) given above.

The luminescent center of the luminescent layer refers to the surface on which the peak of the luminous intensity distribution in the thickness direction of the luminescent layer is located. Usually, the luminescent center of the luminescent layer divides the thickness of the luminescent layer into two parts of equal thickness. The monochromatic light emitted by the light-emitting layer is generally monochromatic light in the visible light region.

Expression (1) is an equation for setting the optical distance L1 between the first light-reflecting interface and the light emitting center of the light emitting layer, the value of which is set so that light having the central wavelength λ1 of the light emitting spectrum of the light emitting layer Mutual enhancement occurs through the interference occurring between the first light reflecting interface and the luminescent center of the luminescent layer.

Expression (2) is an equation expressed as a condition for broadening the band of the interference wavelength λ11 in the above case.

Expression (3) is an equation for setting the optical distance L2 between the second light-reflecting interface and the light-emitting center of the light-emitting layer, the value of which is set so that light having the center wavelength λ1 of the light-emitting spectrum of the light-emitting layer passes through The interference between the second light reflection interface and the luminescent center of the luminescent layer enhances each other, and at the same time, the interference wavelength λ12 is shifted from the central wavelength λ1 of the luminescent spectrum of the luminescent layer (that is, λ12≠λ1).

Equation (6) is an equation expressing the condition for broadening the band of the interference wavelength λ12 in the above-mentioned situation.

Expression (4) is an equation for setting the optical distance L3 between the third light-reflecting interface and the light-emitting center of the light-emitting layer, which sets a value such that light having a center wavelength λ1 of the light-emitting spectrum of the light-emitting layer passes through The interference between the third light reflection interface and the luminescent center of the luminescent layer strengthens each other, and at the same time, the interference wavelength λ13 is shifted from the central wavelength λ1 of the luminescent spectrum of the luminescent layer (that is, λ13≠λ1).

Equation (7) is an equation expressing the condition for broadening the band of the interference wavelength λ13 in the above situation.

Expression (5) is an equation for setting the optical distance L4 between the fourth light-reflecting interface and the light-emitting center of the light-emitting layer. The interference between the four light-reflecting interfaces and the luminescent center of the luminescent layer strengthens each other, and at the same time, the interference wavelength λ14 is shifted from the central wavelength λ1 of the luminescent spectrum of the luminescent layer (that is, λ14≠λ13≠λ1).

Equation (8) is an equation expressing the condition for broadening the band of the interference wavelength λ14 in the above situation.

The interference wavelengths λ11, λ12, λ13 and λ14 in the expressions (1), (3), (4) and (5) are respectively determined by the central wavelength λ1 based on the expressions (2), (6), (7) and (8 )acquired.

The values of the integers n, m, m' and m" are selected according to the needs. In order to increase the amount of light that can be obtained from the light emitting device, it is preferable to set the integer n to a value satisfying the relationship n≤5. It is most preferable to set the integer n to be A value satisfying the relation n=0, and setting the integer m as a value satisfying the relation m=0.

With this light emitting device, the peak of the spectral transmittance curve of the interference filter in the light emitting device is almost flat in the visible light region. In other words, gradients of all light emission color bands may be approximately equal to each other. Therefore, for monochromatic light, the light emitting device can reduce the luminance to be equal to or less than 30% of the luminance at a viewing angle of 0 degrees, and set the value of the chromaticity shift Δuv to satisfy the relationship Δuv≦0.015. In this case, the luminance decreases from the luminance at a viewing angle of 0 degrees to the luminance at a viewing angle of 45 degrees.

Usually, the second light reflection interface is formed by using a metal thin film with a non-zero extinction coefficient and a thickness of at least 5 nm. The metal thin film can be used as a translucent light reflective layer capable of transmitting visible light. In general, each of the third light reflection interface and the fourth light reflection interface may be formed using a difference in refractive index.

According to needs, in addition to the first light reflection interface, the second light reflection interface, the third light reflection interface, and the fourth light reflection interface, a fifth light reflection interface can also be provided to adjust the spectral transmittance curve peak of the interference filter in the light emitting device flatness. In addition, according to needs, at least one of the second light reflection interface, the third light reflection interface, and the fourth light reflection interface and the fifth light reflection interface may be divided into a plurality of light reflection interfaces. In this way, for example, the wavelength band in which the light reflections caused by the second light reflection interface are mutually enhanced can be widened, and the light reflection caused by the third light reflection interface, the light reflection caused by the fourth light reflection interface, and the fifth light reflection can be broadened. The wavelength band in which the light reflections caused by reflective interfaces weaken each other. Therefore, the flat part of the peak of the spectral transmittance curve of the interference filter in the light emitting device can be broadened, and therefore, viewing angle characteristics can be improved.

The light emitting device may be configured as a top surface emission type or a bottom surface emission type. In a top surface emission type light emitting device, a first electrode, an organic layer, and a second electrode are sequentially formed on a substrate to form a laminate. On the other hand, in a bottom surface emission type light emitting device, a second electrode, an organic layer, and a first electrode are sequentially formed on a substrate to form a laminate. The substrate of the top surface emission type light emitting device may be opaque or transparent. That is to say, an opaque substrate or a transparent substrate can be selected as the substrate of the top surface emission type light emitting device according to needs. On the other hand, the substrate of the light emitting device of the bottom surface emission type is a transparent substrate that allows light emitted from a side close to the second electrode to propagate to the outside of the light emitting device.

For improved reliability and other reasons such as the employed configuration, another light reflective layer may be further formed in the light emitting device in some cases to further form another light reflective interface. In such cases, after the formation of the fourth light-reflecting interface required for optical operation, the fifth light-reflecting interface, or more generally the last light-reflecting interface, a layer having a thickness of at least 1 μm is formed thereon such that Interference effects that occur thereafter are almost completely negligible. As the material provided outside the last light reflection interface formed in this case, any material can be used, and a material suitable for realizing a light emitting device can be appropriately selected. Specifically, the material disposed outside the last light-reflecting interface may form one, two or more layers, each layer having a thickness of at least 1 μm. Typical examples of layers are transparent electrode layers, transparent insulating layers, resin layers, glass layers, and air layers. However, the material disposed outside the last light-reflecting interface does not necessarily have to be formed from these layers.

Both the lighting device and the display device may have related art configurations. That is, both lighting devices and display devices may be appropriately configured according to considerations such as application and/or function. A typical display device has a driving substrate in which active devices (such as thin film transistors) are arranged, and each active device is used to provide a display signal for each display pixel to one of the light emitting devices. A typical display device also includes a sealing substrate disposed facing the driving substrate. The light emitting device is disposed between the driving substrate and the sealing substrate. The display device may be a white display device, a black/white display device or a color display device. In the case of a color display device, one of the driving substrate and the sealing substrate is usually a substrate near the second electrode side of each light emitting device. In such a color display device, the color filter is provided on the substrate near the second electrode, and functions as a filter for transmitting light emitted from the side near the second electrode to the substrate near the second electrode.

In addition, the present technology also provides light emitting devices including:

an organic layer sandwiched between the first electrode and the second electrode to serve as an organic layer including a light emitting layer emitting monochromatic light at one position;

a first light reflection interface disposed on a side close to the first electrode to serve as an interface that reflects light emitted from the light-emitting layer so that the reflected light is emitted from a side close to the second electrode; and

The second light-reflecting interface and the third light-reflecting interface are sequentially arranged at positions separated from each other in a direction from the first electrode to the second electrode on the side close to the second electrode.

In this light emitting device,

Symbol L1 represents the optical distance between the first light reflection interface and the luminescent center of the luminescent layer;

Symbol L2 represents the optical distance between the luminescent center and the second light reflection interface;

Symbol L3 represents the optical distance between the luminescent center and the third light reflection interface;

The symbol λ1 represents the central wavelength of the emission spectrum of the light-emitting layer;

The symbols n, m and m' each denote an integer;

The symbols λ11, λ12 and λ13 each denote an interference wavelength;

The length unit nanometer is used as the unit for the wavelengths λ1, λ11, λ12 and λ13;

表示当各波长的光被第一光反射界面反射时观察到的相位变化；symbol

Indicates the phase change observed when the light of each wavelength is reflected by the first light reflecting interface;

表示当各波长的光被第二光反射界面反射时观察到的相位变化；以及symbol

represents the phase change observed when light of each wavelength is reflected by the second light-reflecting interface; and

表示当各波长的光被第三光反射界面反射时观察到的相位变化；symbol

Represents the phase change observed when the light of each wavelength is reflected by the third light reflection interface;

其中n≥0，…(9)The optical distances L1, L2 and L3 satisfy all expressions (9) to (14) given below:

where n≥0,...(9)

λ1-150＜λ11＜λ1+80 ...(10)

λ1-80<λ12<λ1+80 ...(13)

λ1-150<λ13<λ1+150 ...(14)

In addition, the present technology also provides a lighting apparatus employing a plurality of light emitting devices for emitting light having different plain colors from each other, and each light emitting device includes:

an organic layer sandwiched between the first electrode and the second electrode to serve as an organic layer including a light emitting layer emitting monochromatic light at one position;

a first light reflection interface provided on a side close to the first electrode to serve as an interface reflecting light emitted from the light-emitting layer so that the reflected light is emitted from a side close to the second electrode; and

The second light-reflecting interface and the third light-reflecting interface are sequentially arranged at positions separated from each other in a direction from the first electrode to the second electrode on the side close to the second electrode.

In this light emitting device,

Symbol L1 represents the optical distance between the first light reflection interface and the luminescent center of the luminescent layer;

Symbol L2 represents the optical distance between the luminescent center and the second light reflection interface;

Symbol L3 represents the optical distance between the luminescent center and the third light reflection interface;

The symbol λ1 represents the central wavelength of the emission spectrum of the light-emitting layer;

The symbols n, m and m' each denote an integer;

The symbols λ11, λ12 and λ13 each denote an interference wavelength;

The length unit nanometer is used as the unit for the wavelengths λ1, λ11, λ12 and λ13;

表示当各波长的光被第一光反射界面反射时观察到的相位变化；symbol

Indicates the phase change observed when the light of each wavelength is reflected by the first light reflecting interface;

表示当各波长的光被第二光反射界面反射时观察到的相位变化；以及symbol

represents the phase change observed when light of each wavelength is reflected by the second light-reflecting interface; and

表示当各波长的光被第三光反射界面反射时观察到的相位变化；symbol

Represents the phase change observed when the light of each wavelength is reflected by the third light reflection interface;

The optical distances L1, L2, and L3 satisfy all of the expressions (9) to (14) given above.

In addition, the present technology also provides a lighting apparatus employing a plurality of light emitting devices for emitting light having different plain colors from each other, and each light emitting device includes:

an organic layer sandwiched between the first electrode and the second electrode to serve as an organic layer including a light emitting layer emitting monochromatic light at one position;

a first light reflection interface disposed on a side close to the first electrode to serve as an interface that reflects light emitted from the light-emitting layer so that the reflected light is emitted from a side close to the second electrode; and

The second light-reflecting interface and the third light-reflecting interface are sequentially arranged at positions separated from each other in a direction from the first electrode to the second electrode on the side close to the second electrode.

In this light emitting device,

Symbol L1 represents the optical distance between the first light reflection interface and the luminescent center of the luminescent layer;

Symbol L2 represents the optical distance between the luminescent center and the second light reflection interface;

Symbol L3 represents the optical distance between the luminescent center and the third light reflection interface;

The symbol λ1 represents the central wavelength of the emission spectrum of the light-emitting layer;

The symbols n, m and m' each denote an integer;

The symbols λ11, λ12 and λ13 each denote an interference wavelength;

The length unit nanometer is used as the unit for the wavelengths λ1, λ11, λ12 and λ13;

表示当各波长的光被第一光反射界面反射时观察到的相位变化；symbol

Indicates the phase change observed when the light of each wavelength is reflected by the first light reflecting interface;

symbol represents the phase change observed when light of each wavelength is reflected by the second light-reflecting interface; and

表示当各波长的光被第三光反射界面反射时观察到的相位变化；symbol

Represents the phase change observed when the light of each wavelength is reflected by the third light reflection interface;

The optical distances L1, L2, and L3 satisfy all of the expressions (9) to (14) given above.

The light-emitting device described above is different from the light-emitting device described above in that although the light-emitting device described above requires a first light-reflecting interface, a second light-reflecting interface, and a third light-reflecting interface, the light-emitting device described above does not A fourth light reflecting interface is required.

Likewise, the lighting device described above is different from the lighting device described above in that although the light-emitting device described above requires a first light-reflecting interface, a second light-reflecting interface, and a third light-reflecting interface, the light-emitting device described above The device does not require a fourth light reflective interface.

Also, the above-described display device is different from the previously-described display device in that although the above-described light-emitting device requires a first light-reflecting interface, a second light-reflecting interface, and a third light-reflecting interface, the above-described light-emitting The device does not require a fourth light reflective interface.

The fourth light reflection interface is provided as required, and is used as a light reflection interface for adjusting the flatness of the peak of the spectral transmittance curve of the interference filter in the light emitting device. Other descriptions of the previously explained light emitting device, lighting device and display device are valid for the above described light emitting device, lighting device and display device, as long as the other descriptions do not deviate from the characteristics of the above described light emitting device, lighting device and display device.

According to the present technology, it is possible to realize a light emitting device capable of emitting light that can be well captured over a wide wavelength band and that can significantly reduce the viewing angle dependence of luminance and the viewing angle dependence of hue of monochromatic light.

Furthermore, according to the present technology, it is possible to realize a lighting device that has little viewing angle dependence, has good light distribution characteristics, and is easily and efficiently manufactured.

Furthermore, according to the present technology, it is possible to realize a display device capable of displaying a high-quality image with little viewing angle dependence, and which can be easily and efficiently manufactured.

Description of drawings

1 is a cross-sectional view showing an organic EL device according to a first embodiment;

2 is a diagram roughly showing a spectral transmittance curve of an interference filter of a first light reflection interface in an organic EL device according to a first embodiment;

3 is a graph roughly showing the spectral transmittance curve of the interference filter of the first light reflection interface and the spectral transmittance curve of the combined interference filter of the first and second light reflection interfaces in the organic EL device according to the first embodiment diagram of

4 is a graph roughly showing the spectral transmittance curve of the interference filter of the first light reflection interface, the spectral transmittance curve of the composite interference filter of the first and second light reflection interfaces in the organic EL device according to the first embodiment, and a graph of the spectral transmittance curves of the composite interference filter of the first, second and third light reflective interfaces;

5 is a diagram roughly showing spectral transmittance curves of synthetic interference filters of first, second, third and fourth light reflection interfaces in the organic EL device according to the first embodiment;

6 is a diagram roughly showing viewing angle characteristics of chromaticity of the organic EL device according to the first embodiment;

7 is a diagram roughly showing viewing angle characteristics of luminance of the organic EL device according to the first embodiment;

8 is a diagram roughly showing a plurality of spectral transmittance curves, each of which is similar to the spectral transmittance curve of FIG. 5 and based on the central wavelength λ1 being 575 nm (that is, λ1=575 nm) according to the expression ( 2) the calculated value as the curve of the interference filter of the value of the interference wavelength λ11;

9 is a diagram roughly showing a spectral reflection curve of the organic EL device according to the first embodiment;

10 is a schematic diagram showing the spectral transmittance curves and the first, second, third, third, and first synthetic interference filters of the first, second, third, and fourth light reflection interfaces in the organic EL device according to the third embodiment. The spectral transmittance curves of the synthetic interference filters of the fourth and fifth light-reflecting interfaces;

11 is a diagram roughly showing viewing angle characteristics of chromaticity of an organic EL device according to a third embodiment;

FIG. 12 is a diagram roughly showing viewing angle characteristics of luminance of an organic EL device according to a third embodiment;

13 is a cross-sectional view showing a top surface light-emitting organic EL device according to the first embodiment;

14 is a sectional view showing a lower surface light-emitting organic EL device according to a second embodiment;

15 is a sectional view showing an organic EL lighting device according to a fourth embodiment;

Fig. 16 is a cross-sectional view showing an organic EL lighting device according to a fifth embodiment.

Detailed ways

Embodiments of the present technology will be described below. Embodiments are described in sections arranged in the following order.

1. First Embodiment (Organic EL Device)

2. Second Embodiment (Organic EL Device)

3. Third Embodiment (Organic EL Device)

4. Fourth Embodiment (Organic EL Lighting Equipment)

5. Fifth Embodiment (Organic EL Display Device)

1. First Embodiment (Organic EL Device)

FIG. 1 is a cross-sectional view of an organic EL device according to a first embodiment.

As shown in FIG. 1, in this organic EL device, an organic layer 13 is sandwiched between a first electrode 11 and a second electrode 12, serving as an organic layer including a light emitting layer 13a emitting monochromatic light at one position. The luminescent center of the luminescent layer 13a is represented by symbol O. The organic layer 13 includes portions above and below the light emitting layer 13a. Each of these portions above and below the light-emitting layer 13a includes layers such as a hole injection layer, a hole transfer layer, an electron transfer layer, and an electron injection layer as necessary, as in conventionally known organic EL devices. Same. In this case, the second electrode 12 is generally a transparent electrode that transmits visible light so that light is emitted from a side close to the second electrode 12 . The light emitting layer 13a generally emits monochromatic light in the visible light region. The emission wavelength of the light emitting layer 13a is selected according to the color of light to be emitted by the organic EL device. Between the organic layer 13 and the second electrode 12 , the metal thin film 14 , the conductive transparent layer 15 and the conductive transparent layer 16 are sequentially disposed at positions separated from each other in the direction from the first electrode 11 to the second electrode 12 . The metal thin film 14, the transparent layer 15 and the transparent layer 16 are all transmission layers, and the light emitted by the light emitting layer 13a can pass through these transmission layers. Each of the transparent layer 15 and the transparent layer 16 may be configured as a laminate including two or more layers as needed. The first electrode 11, the second electrode 12, the organic layer 13, the light emitting layer 13a, the metal thin film 14, the transparent layer 15 and the transparent layer 16 can all be selected from conventionally known materials as required.

The refractive index of the organic layer 13 is different from that of the first electrode 11 . The first light reflection interface 17 is formed between the organic layer 13 and the first electrode 11 due to the difference between these refractive indices. According to needs, the first light reflection interface 17 may be disposed at a position separated from the first electrode 11 . The first light reflection interface 17 functions to reflect the light emitted by the light emitting layer 13 a, so that the reflected light is emitted from a side close to the second electrode 12 .

The metal thin film 14 is made of a metal material with a non-zero extinction coefficient and at least 5 nm thick. The second light reflection interface 18 is formed between the organic layer 13 and the metal thin film 14 .

Likewise, the refractive index of the transparent layer 15 is different from that of the transparent layer 16 . Due to the difference between these refractive indices, a third light reflection interface 19 is formed between the transparent layer 15 and the transparent layer 16 .

Also, the refractive index of the transparent layer 16 is different from that of the second electrode 12 , and a fourth light reflection interface 20 is formed between the transparent layer 16 and the second electrode 12 due to the difference between these refractive indices.

In Fig. 1, symbol L1 represents the optical distance between the first light-reflecting interface 17 and the luminous center O of the light-emitting layer 13a, symbol L2 represents the optical distance between the luminous center O and the second light-reflecting interface 18, and symbol L3 represents The optical distance between the luminescence center O and the third light reflection interface 19 , and the symbol L4 represents the optical distance between the luminescence center O and the fourth light reflection interface 20 . The optical distances L1, L2, L3, and L4 are set to values satisfying all the equations (1) to (8) given above.

More specifically, the optical distance L1 is set to such a value that the light having the center wavelength λ1 of the luminescence spectrum of the luminescent layer 13a is mutually separated by the interference occurring between the first light reflection interface 17 and the luminescence center O of the luminescent layer 13a. enhanced.

Likewise, the optical distance L2 is set to such a value that the lights having the central wavelength λ1 of the luminescent spectrum of the luminescent layer 13a are mutually enhanced by the interference occurring between the second light reflection interface 18 and the luminescent center O of the luminescent layer 13a. .

Likewise, the optical distance L3 is set to such a value that lights having a central wavelength λ1 of the luminescence spectrum of the luminescent layer 13a are mutually attenuated by interference occurring between the third light reflection interface 19 and the luminescence center O of the luminescent layer 13a. .

Likewise, the optical distance L4 is set to such a value that the lights having the central wavelength λ1 of the luminescence spectrum of the luminescence layer 13a are mutually weakened by the interference occurring between the fourth light reflection interface 20 and the luminescence center O of the luminescence layer 13a. .

As an example, the state of λ1 = 575 nm is expressed by the following equation, which satisfies Expressions (1) to (4). At this time, the light emitting layer 13 a exists at a position where the 0th (n=0 in expression (1)) interference occurs. Therefore, the transmittance is high over a wide wavelength band, and as evident from expression (2), the interference wavelength λ1 can also be significantly shifted from the central wavelength λ1 of the emission spectrum of the light emitting layer 13a. For the transmittance, the reader is referred to FIG. 2 , which shows the transmittance of the interference filter of the first reflective interface 17 of the luminescent layer 13a. In FIG. 2 , the first light-reflecting interface 17 is shown as the light-reflecting interface 1 .

For the above equation, the following relationship applies:

λ1-150＝425＜λ11＝540＜λ1+80＝655nm ...(2)'

折射率n°和消光系数k满足等式N＝n°-jk，其中符号N表示第一电极11的复折射率。关于相变计算的更多信息，建议读者参考文献，如Pergamon Press在1974年出版的MaxBorn和Emil Wolf著的“Principles of Optics”。有机层13的折射率和透明层15和16的折射率可利用光谱椭圆对称测量(spectroscopic ellipsometrymeasurement)设备测量。Based on these equations, the phase transition can be calculated using the refractive index n°, the extinction coefficient k, and the refractive index _n0 of the organic layer 13 in contact with the first electrode 11

The refractive index n° and the extinction coefficient k satisfy the equation N=n°−jk, where the symbol N represents the complex refractive index of the first electrode 11 . About phase change For more information on calculations, the reader is advised to refer to literature such as "Principles of Optics" by Max Born and Emil Wolf, Pergamon Press, 1974. The refractive index of the organic layer 13 and the refractive indices of the transparent layers 15 and 16 can be measured using a spectroscopic ellipsometry measurement device.

的典型计算说明如下。假定第一电极11由Al(铝)合金制成。在此情况下，对于波长为575nm的光(对应于第一发光层13a的发光谱的中心波长λ1)，n°＝0.908且k＝5.927。如果有机层13的折射率为1.75(n₀＝1.75)，相变

可表达为下式：phase change

A typical calculation of is described below. It is assumed that the first electrode 11 is made of Al (aluminum) alloy. In this case, n°=0.908 and k=5.927 for light having a wavelength of 575 nm (corresponding to the central wavelength λ1 of the emission spectrum of the first light-emitting layer 13 a ). If the refractive index of the organic layer 13 is 1.75 (n ₀ =1.75), the phase transition

Can be expressed as the following formula:

则相变

为-2.618弧度(也就是，

将该相变

值代入表达式(1)’中，得到光学距离L1的值为101纳米(也就是L1＝101nm)。If you consider the range

phase change

is -2.618 radians (that is,

change the phase

Substituting the values into the expression (1)', the value of the optical distance L1 is obtained to be 101 nm (that is, L1 = 101 nm).

进一步增加π弧度。另一方面，如果第一电极11的折射率n°小于有机层13的折射率n₀，则相变

进一步增加0弧度。It should be noted that if the refractive index n° of the first electrode 11 is greater than the refractive index n ₀ of the organic layer 13, the phase transition

Further increases in π radians. On the other hand, if the refractive index n° of the first electrode 11 is smaller than the refractive index n ₀ of the organic layer 13, the phase transition

Add 0 radians further.

At this time, the state of the interference filter of the first light reflection interface 17 of the light emitting layer 13a satisfies the mutual enhancement condition. Therefore, as shown in FIG. 2 , the spectral transmittance curve has a peak portion representing an increase in the light harvesting degree. However, since observation is performed in an oblique direction, the wavelength band of the interference filter is shifted toward smaller wavelengths, resulting in changes in brightness and hue.

Then, a second light reflection interface 18 is formed between the organic layer 13 with a refractive index n ₀ of 1.75 (ie, n ₀ =1.75) and the metal thin film 14 with a typical thickness of 6.0 nm. Subsequently, a third light reflection interface 19 is formed between the transparent layer 15 having a typical refractive index of 1.8 and the transparent layer 16 having a refractive index different from the typical refractive index of the transparent layer 15 . For example, the refractive index of the transparent layer 16 is 1.5. Then, a fourth light reflection interface 20 is formed between the transparent layer 16 and the second electrode 12 having a different refractive index from the transparent layer 16 . For example, the refractive index of the second electrode 12 is 1.8.

As a material for manufacturing the transparent layer 15 having a refractive index of 1.8 and the second electrode having a refractive index of 1.8, for example, ITO (indium tin oxide) or the like which selects an oxygen component can be used. In this case, if the optical distance L2 is set to a typical value of 108nm, the optical distance L3 is set to a typical value of 180nm, and the optical distance L4 is set to a typical value of 230nm, the light reflection of the second light reflection interface 18, the third The light reflection of the light reflection interface 19 and the light reflection of the fourth light reflection interface 20 satisfy the conditions given below. The condition that the light reflection of the second light reflection interface 18 satisfies is the mutual enhancement condition, λ11=λ12 or λ11≈λ12. On the other hand, the condition that the light reflection of the third light reflection interface 19 satisfies and the condition that the light reflection of the fourth light reflection interface 20 satisfies is that the light reflection is mutually weakened while the interference wavelengths λ13 and λ14 are shifted from the central wavelength λ1 ( That is, the condition of λ13≠λ14≠λ1). These conditions are expressed by the following equations:

The unit of the interference wavelengths λ12, λ13, and λ14 is the length unit nanometer.

和可以与上述相变

相同的方式计算。The phase transition for the above equation

and can be phase-transformed with the above

Calculated in the same way.

Therefore, all the conditions expressed by Expressions (1) to (8) are satisfied.

3 is a diagram roughly showing the spectral transmittance curve of the interference filter of the first light reflection interface 17 and the spectral transmittance curve of the composite interference filter of the first light reflection interface 17 and the second light reflection interface 18 . In FIG. 3 , the first light reflection interface 17 and the second light reflection interface 18 are respectively shown as light reflection interface 1 and light reflection interface 2 . In this case, the wavelength condition of the first light reflection interface 17 is close to the wavelength condition of the second light reflection interface 18 . For wavelengths close to the 550nm wavelength, the transmittance is improved. However, since the peaks of the spectral transmittance curves of the synthetic interference filters of the first light reflection interface 17 and the second light reflection interface 18 are enhanced, green light cannot be well-balanced. Furthermore, since a flat portion cannot be obtained in this spectral transmittance curve, the viewing angle characteristic exhibits a significant change in both luminance and hue.

Fig. 4 roughly shows the spectral transmittance of the interference filter of the first light reflective interface 17, the spectral transmittance curve of the composite interference filter of the first light reflective interface 17 and the second light reflective interface 18, and in order to illustrate the first light reflective interface A diagram of the spectral transmittance curves of the synthetic interference filter of the first light reflection interface 17 , the second light reflection interface 18 and the third light reflection interface 19 of the effect of the three light reflection interfaces 19 . In FIG. 4 , the first light reflection interface 17 , the second light reflection interface 18 and the third light reflection interface 19 are shown as light reflection interface 1 , light reflection interface 2 and light reflection interface 3 , respectively. As shown in FIG. 4 , in this state, the spectral transmittance curves of the synthesized interference filters of the first reflective interface 17 , the second reflective interface 18 and the third reflective interface 19 are still not completely flat. This is because only with the third light reflection interface 19 formed based on the difference in refractive index, the reflection intensity is small, and thus the mutual reinforcement formed by the metal thin film 14 cannot be sufficiently canceled out.

5 is a diagram roughly showing the spectral transmittance curves of the interference filters of the first light reflection interface 17, the second light reflection interface 18, the third light reflection interface 19 and the fourth light reflection interface 20, thereby showing the first The effect of four light reflection interfaces 20 . It is apparent from FIG. 5 that in the green light region, an almost flat interference filter is formed.

FIG. 6 is a graph roughly showing viewing angle characteristics of chromaticity of green light in this state, and FIG. 7 is a graph roughly showing viewing angle characteristics of luminance of green light in this state. It is evident from FIG. 7 that at least 85% of the luminance obtained at a viewing angle of 0 degrees can be maintained at a viewing angle of 45 degrees. On the other hand, it is evident from FIG. 6 that a relative chromaticity shift Δuv≦0.015 can also be achieved for chromaticity.

Fig. 5 shows calculation results for λ11 = 540 nm. (The reader is referred to expression (2)'). However, the same result can also be obtained if the value of the interference wavelength λ11 is within the range defined by the expression (2). That is, FIG. 8 is a diagram roughly showing a spectral transmittance curve of an interference filter based on a value calculated according to Expression (2) based on a center wavelength λ1 of 575 nm (that is, λ1=575 nm) as a value of the interference wavelength λ11 picture. It is apparent from FIG. 8 that if the value of the interference wavelength λ11 is within the range according to the expression (2), in the region of green light, an almost flat interference filter can be formed.

According to the first embodiment described above, in the organic EL device, the organic layer 13 sandwiched between the first electrode 11 and the second electrode 12 has the light emitting layer 13a for emitting monochromatic light, typically, for example, Monochromatic light in the visible region. On the side close to the first electrode 11, a first light reflection interface 17 is formed. On the other hand, the second light reflection interface 18 , the third light reflection interface 19 , and the fourth light reflection interface 20 are formed on the side close to the second electrode 12 from which light is emitted.

In addition, the optical distances L1, L2, L3, and L4 shown in FIG. 1 are each set to a value satisfying all expressions (1) to (8). As a result, the transmittance of the interference filter in the organic EL device is high in the wavelength band of monochromatic light such as green light, so that light can be well captured in this wavelength band.

In addition, organic EL devices can significantly reduce viewing angle dependence of luminance and viewing angle dependence of chromaticity for green light, for example.

Furthermore, even if the thickness of the transparent layer 15 and the thickness of the transparent layer 16 are fixed, the organic EL device allows the color of emitted light to be selected by designing the thickness of the light emitting layer 13a and the like. Therefore, if organic EL devices whose emitted light colors are different from each other are to be manufactured, it is only necessary to change, for example, the thickness of the light emitting layer 13a, making it easy to efficiently manufacture organic EL devices whose emitted light colors are different from each other.

In addition, since the transmittance of the interference filter in the organic EL device is high, the power consumption of the device is low.

The second light reflection interface 18 is formed at a position where light emitted from the light emitting layer 13a is amplified. However, since the metal thin film 14 with a thickness equal to or greater than 5 nm is formed on the second light reflection interface 18, in addition to the amplification effect of the microcavity (small resonator), the extinction coefficient of the metal thin film 14 causes multiple reflections to occur during multiple reflections. Light absorption makes it possible to produce the effect of eliminating the reflection of external light. The spectral reflectance characteristics in this case are shown in FIG. 9 . Furthermore, reflection of external light can be further suppressed by providing a color filter on the light exit side in the organic EL device. The effect of eliminating reflection of external light enables the organic EL device to display vivid images even if it is used in a position where external light is received.

2. Second Embodiment (Organic EL Device)

The organic EL device according to the second embodiment is obtained by dividing both the third light reflecting interface 19 and the fourth light reflecting interface 20 included in the organic EL device according to the first embodiment into two light reflecting interfaces (that is, respectively front light reflection interface and back light reflection interface) to broaden the wavelength band of the anti-phase interference condition expressed by expressions (4) and (5). That is, in the case of Expression (4), for example, the third light reflection interface 19 is divided into a front light reflection interface and a rear light reflection interface separated from each other by a distance Δ. As the third light reflection interface 19 is divided into a front light reflection interface and a rear light reflection interface, the optical distance L3 becomes L3+Δ and L3−Δ. Therefore, the band of the interference wavelength λ13 for which the expression (4) holds increases. This description applies to the wavelength band of the interference wavelength λ14 used in the expression (5).

The second embodiment offers the same advantages as the first embodiment. In addition, it is also possible to broaden the wavelength band of the anti-phase interference conditions expressed by expressions (4) and (5). Therefore, the second embodiment also has an advantage that the viewing angle characteristics of the organic EL device can be further improved.

3. Third Embodiment (Organic EL Device)

If the organic EL device is required to have a wider viewing angle range, in some cases, the spectral transmittance curve of the interference filter may be required to have flatness in a wider wavelength band. In such cases, the center wavelengths of the interference caused by the third light reflection interface 19 and the fourth light reflection interface 20 need to be separated from each other. However, if the center wavelengths of the interference caused by the third light reflecting interface 19 and the fourth light reflecting interface 20 are too different from each other, the flatness of the peak of the spectral transmittance curve of the interference filter is lost, making it difficult to maintain viewing angle characteristics. In order to solve this problem, in addition to the third light reflection interface 19 and the fourth light reflection interface 20 included in the organic EL device according to the first embodiment, according to the third embodiment capable of improving viewing angle characteristics, a fifth light reflection interface is newly provided. Light reflecting interface.

For the fifth light reflection interface, a mutual enhancement condition exists within the range of λ1±15 nm, where the symbol λ1 represents the central wavelength of the emission spectrum of the light emitting layer 13a. The curve (a) shown in FIG. 10 is the first light reflection interface 17, the second light reflection interface 18, and the third light reflection interface 19 included in the organic EL device without the fifth light reflection interface according to the first embodiment. and the spectral transmittance curve of the synthetic interference filter of the fourth light reflection interface 20 . In this case, the central portion of the spectral transmittance curve is unintentionally concave due to the wide band obtained by making the interference wavelengths λ13 and λ14 different from each other by equal to or more than 50 nm. Also, for larger viewing angles, non-uniform luminance variations occur.

On the other hand, curve (b) shown in Fig. 10 is the composite interference of the first light reflection interface 17, the second light reflection interface 18, the third light reflection interface 19, the fourth light reflection interface 20 and the fifth light reflection interface The spectral transmittance curve of the filter, these light reflection interfaces are included in the organic EL device according to the third embodiment. By setting the fifth light-reflecting interface under mutual enhancement conditions to the central wavelength λ1 of the light-emitting spectrum of the light-emitting layer 13a, it is obvious from the curve (b) that the peak part of the spectral transmittance curve of the interference filter can be made in a wide wavelength band upper flat.

11 is a diagram roughly showing viewing angle characteristics of chromaticity of an organic EL device including a fifth light reflection interface according to a third embodiment, and FIG. 12 is a graph roughly showing luminance of an organic EL device according to a third embodiment A diagram of the viewing angle characteristics of . As apparent from FIGS. 11 and 12 , the organic EL device according to the third embodiment can further improve viewing angle characteristics of chromaticity and luminance, compared with the organic EL device according to the first embodiment.

The third embodiment provides the same advantages as the first embodiment. In addition, it is also possible to broaden the wavelength band of the antiphase interference conditions expressed by Expressions (4) and (5). Thus, the third embodiment also has an advantage that the luminance viewing angle characteristics and the chromaticity viewing angle characteristics of the organic EL device can be further improved.

first embodiment

The first example is an example of the first embodiment.

Fig. 13 is a cross-sectional view showing the organic EL device according to the first embodiment. The top surface light emitting organic EL device is a top surface light emitting type organic EL device. As shown in FIG. 13, the organic EL device is constructed by forming a laminated body on a substrate 21 serving as the lowermost layer. The laminate is formed by sequentially forming a first electrode 11 , an organic layer 13 , a metal layer 14 , a transparent layer 15 , a transparent layer 16 , and a second electrode 12 in an upward direction. Then, a passivation film 22 is provided on the second electrode 12 . The organic layer 13 includes a light emitting layer 13a.

The substrate 21 is generally a transparent glass substrate or a semiconductor substrate such as a silicon substrate. The substrate 21 may also be configured as a flexible substrate.

The first electrode 11 serves as an anode and also serves as a light reflection layer. The first electrode 11 is usually formed of a light reflective material such as Al (aluminum), aluminum alloy, Pt (platinum), Au (gold), Cr (chrome) or W (tungsten). It is preferable to set the thickness of the first electrode 11 in the range of 100 nm to 300 nm. The first electrode 11 may be a transparent electrode. In this case, since the first light reflection interface 17 will be formed between the first electrode 11 and the substrate 21, it is preferable to use the first electrode 11 as a light reflection material formed of a light reflection material such as Pt, Au, Cr, or W. reflective layer.

The organic layer 13 has a structure configured by sequentially forming a hole injection layer, a hole transport layer, a light emitting layer 13a, an electron transport layer, and an electron injection layer in an upward direction to form a laminate. The hole injection layer is generally composed of HAT (hexaazatriphenylene). The hole transfer layer is usually made of α-NPD[N,N'-bis(1-naphthyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine ]constitute. The light-emitting layer 13a is formed with a light-emitting material that emits red, green, or blue light. As a light-emitting material emitting red light, a material obtained by doping rubrene serving as a host material with a succinimide ester-boron complex can be utilized. As a light-emitting material that emits green light, Alq3 (tris(8-quinolinolato)aluminum complex) can be used. As a light-emitting material that emits blue light, materials generally produced as follows can be utilized. Specifically, as a host material, AND (9,10-bis(2-naphthyl)anthracene) was evaporated to form a film with a thickness of 20 nm. At this time, a diaminochrysene derivative used as a dopant material was doped with AND at a relative film thickness ratio of 5%, so that the film could be used as a light emitting material emitting blue light. The electron transport layer is generally composed of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) or the like. The electron injection layer is usually made of LiF (lithium fluoride) or the like.

The layer thickness constituting the organic layer 13 is set to the value described below. Preferably, the thickness of the hole injection layer is set within the range of 1 nm to 20 nm, the thickness of the hole transfer layer is set within the range of 15 nm to 100 nm, the thickness of the light emitting layer 13a is set within the range of 5 nm to 50 nm, and the electron injection layer 13a is preferably set within the range of 5 nm to 50 nm. Layer and electron transfer layer thicknesses are set in the range of 15nm to 200nm. The thicknesses of the organic layer 13 and the layers constituting the organic layer 13 are set to values at which the optical film thickness allows the above-described operations to be performed.

The second light reflection interface 18 is formed due to the formation of the metal thin film 14 on the organic layer 13 . On the other hand, the third light reflection interface 19 is formed by utilizing the difference in refractive index between the transparent layer 15 and the transparent layer 16 . Likewise, the fourth light reflection interface 20 is formed by utilizing the difference in refractive index between the transparent layer 16 and the second electrode 12 . Each of transparent layer 15 and transparent layer 16 does not have to be a single layer. That is, each transparent layer 15 and transparent layer 16 may also be a laminate composed of two or more transparent layers having different refractive indices from each other according to a desired flat wavelength band and desired viewing angle characteristics.

The second electrode 12 for harvesting the light emitted by the light-emitting layer 13a is composed of ITO and/or oxide, which are materials generally used for manufacturing transparent electrodes. Typical examples of such oxides are indium oxide and zinc oxide. The second electrode 12 serves as a cathode. The thickness of the second electrode 12 is generally in the range of 30nm to 3000nm.

The passivation film 22 is composed of a transparent derivative. It is not necessarily required that the refractive index of the transparent derivative used to form the passivation film 22 is in the same order as that of the material used to manufacture the second electrode 12 . If the second electrode 12 is also used as the transparent layer 16 , an interface is formed using a difference in refractive index between the second electrode 12 and the passivation film 22 . In this case, the interface may be formed in the same manner as the fourth light reflection interface 20 . Typical examples of transparent derivatives are SiO ₂ (silicon dioxide) and SiN (silicon nitride). The thickness value of the passivation film 22 is usually in the range of 500 nm to 10000 nm.

The metal thin film 14 is generally made of metal materials such as Mg (magnesium), Ag (silver) or any alloy thereof. The thickness of the metal thin film 14 is appropriately set to a value equal to or greater than 5 nm. Utilizing the metal thin film 14 as the light reflection layer can produce an amplification effect whose intensity is greater than that of ordinary interference. In addition, the second light reflection interface 18 formed by the metal thin film 14 provides a wide wavelength band and high transmittance.

second embodiment

The second embodiment is another example of the first embodiment.

Fig. 14 is a cross-sectional view showing an organic EL device according to a second embodiment. The organic EL device is a bottom surface emission type organic EL device. As shown in FIG. 14, an organic EL device is formed by forming a laminate on a substrate 21 serving as the lowermost layer. The laminate is formed by sequentially forming passivation film 22 , second electrode 12 , transparent layer 16 , transparent layer 15 , metal thin film 14 , organic layer 13 , and first electrode 11 in an upward direction. In this case, the light emitted from the second electrode 12 passes through the substrate 21 and is taken outside the organic EL lighting device. The rest of the second embodiment is the same as the first embodiment.

4. Fourth Embodiment (Organic EL Lighting Equipment)

Fig. 15 is a cross-sectional view showing an organic EL lighting device according to a fourth embodiment.

As shown in FIG. 15 , in this organic EL lighting device, a first organic EL device D1 , a second organic EL device D2 , and a third organic EL device D3 are mounted on a transparent substrate 30 . The first organic EL device D1, the second organic EL device D2, and the third organic EL device D3 are all organic EL devices according to any one of the first to third embodiments. In this configuration, the first organic EL device D1 , the second organic EL device D2 , and the third organic EL device D3 are all oriented such that the second electrode 12 is located on the lower side so as to be exposed to the substrate 30 . Therefore, the light emitted from the second electrode 12 passes through the substrate 30 and is captured outside the organic EL lighting device.

The sealing substrate 31 is disposed on the substrate 30 to face the substrate 30 by sandwiching the first organic EL device D1 , the second organic EL device D2 , and the third organic EL device D3 between the substrate 30 and the sealing substrate 31 . The peripheries of the substrate 30 and the sealing substrate 31 are sealed with a sealing material 32 .

The planar shape of the organic EL lighting device can be selected according to needs. But the planar shape of the organic EL lighting device is usually a square or a rectangle. FIG. 15 shows only combinations including the first organic EL device D1, the second organic EL device D2, and the third organic EL device D3. However, a plurality of such combinations may be mounted on the substrate 30 in a desired layout, as desired. Except for the first organic EL device D1, the second organic EL device D2, and the third organic EL device D3, configuration details of other elements used in the organic EL lighting device are the same as those of generally known organic EL lighting devices. In addition, the configuration other than the configuration of other elements is also the same as that of a generally known organic EL lighting device.

The fourth embodiment utilizes a first organic EL device D1, a second organic EL device D2, and a third organic EL device D3, which are organic EL devices according to any one of the first to third embodiments. Therefore, an organic EL lighting device can be implemented as a planar light source with little viewing angle dependence and good light distribution characteristics. In other words, it is possible to realize a planar light source having extremely small changes in intensity and color caused by the direction of illumination and having good light distribution characteristics. In addition, by designing the light-emitting layer 13a, the color of the light emitted by each of the first organic EL device D1, the second organic EL device D2, and the third organic EL device D3 can be selected, so that in addition to white emitted light, Get a variety of different colors of emitted light. Therefore, an organic EL lighting device having good color rendering characteristics can be realized. In addition, organic EL lighting devices can be easily and efficiently manufactured.

5. Fifth Embodiment (Organic EL Display Device)

16 is a cross-sectional view showing an organic EL display device according to a fifth embodiment. This organic EL display device is an active matrix type.

As shown in FIG. 16, in this organic EL display device, a driving substrate 40 and a sealing substrate 41 are arranged to face each other. The peripheries of the driving substrate 40 and the sealing substrate 41 are sealed with a sealing material 42 . A plurality of pixels are laid out on a generally glass transparent substrate in the driving substrate 40 to form a two-dimensional array. Each pixel includes a first organic EL device D1, a second organic EL device D2, and a third organic EL device D3, which are organic EL devices according to any one of the first to third embodiments. On the driving substrate 40, a thin film transistor is formed for each pixel to serve as an active device for driving the pixel. In addition, scanning lines, current supply lines, and data lines each for driving thin film transistors of the respective pixels are further provided, formed in the vertical and horizontal directions. Each thin film transistor provided for each pixel receives a display signal generated for that pixel. The display signal drives the pixels to display an image on the organic EL display device. Except for the first organic EL device D1, the second organic EL device D2, and the third organic EL device D3, configuration details of other elements used in the organic EL display device are the same as those of generally known organic EL display devices. In addition, the configuration other than the configuration of other elements is also the same as that of a generally known organic EL display device.

The organic EL display device can be used not only as a black/white organic EL display device but also as a color organic EL display device. If the organic EL display device is used as a color organic EL display device, the RGB color filters are provided on the drive substrate 40 side. Specifically, RGB color filters are disposed between the driving substrate 40 and the second electrodes 12 of the first organic EL device D1, the second organic EL device D2 and the third organic EL device D3.

The fifth embodiment utilizes a first organic EL device D1, a second organic EL device D2, and a third organic EL device D3, each of which is an organic EL device according to any one of the first to third embodiments. Therefore, an organic EL display device capable of displaying a high-quality image with extremely small changes in luminance and hue due to viewing angles can be realized. In addition, organic EL display devices are easily and efficiently manufactured.

So far, the embodiment and the examples have been specifically described. However, implementation of the present technology is by no means limited to these embodiments and examples. That is to say, the embodiment modes and examples can be further changed to further realize the present technology.

For example, the embodiments and examples employ various numerical values, structures, configurations, shapes, materials, and the like. However, these numerical values, structures, configurations, shapes, materials, etc. are only typical representatives. The embodiments and examples may take on other values, other structures, other configurations, other shapes, other materials, etc., as desired.

The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2011-059666 filed in the Japan Patent Office on Mar. 17, 2011, the entire content of which is hereby incorporated by reference.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made depending on design requirements and other factors insofar as they are within the scope of the claims and the equivalents thereof.

Claims (21)

1. luminescent device comprises:

Organic layer is clipped between first electrode and second electrode with as comprising the organic layer of launching monochromatic luminescent layer a position;

The first smooth reflecting interface is arranged near said first electrode, one side to make from penetrating this catoptrical interface near said second electrode, one side as the light of reflection from said luminescent layer emission; And

The second smooth reflecting interface, the 3rd smooth reflecting interface and the 4th smooth reflecting interface are setting gradually near the position that is separated from each other of said second electrode, one side on from said first electrode to the direction of said second electrode,

Wherein, symbol L1 representes the optical distance between the luminescence center of the said first smooth reflecting interface and said luminescent layer;

Symbol L2 representes the optical distance between the said luminescence center and the said second smooth reflecting interface;

Symbol L3 representes the optical distance between said luminescence center and the said the 3rd smooth reflecting interface;

Symbol L4 representes the optical distance between said luminescence center and the said the 4th smooth reflecting interface;

The centre wavelength of the luminous spectrum of the said luminescent layer of sign of lambda 1 expression;

Symbol n, m, m ' and m " all represent integer;

Sign of lambda 11, λ 12, λ 13 and λ 14 all represent to interfere wavelength;

The long measure nanometer is as the unit of said wavelength X 1, λ 11, λ 12, λ 13 and λ 14;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said first smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said second smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said the 3rd smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said the 4th smooth reflecting interface reflex time;

Said optical distance L1, L2, L3 and L4 satisfy all expression formulas given below (1) and arrive (8):

be n>=0 wherein ... (1)

λ1-150＜λ11＜λ1+80 …(2)

λ1-80＜λ12＜λ1+80 …(6)

λ1-150＜λ13＜λ1+150 …(7)

λ1-150＜λ14＜λ1+150 …(8)。

2. luminescent device according to claim 1, wherein, almost smooth or gradient is each other about equally in the visible region at the peak of the spectral transmission curve of interference filter in the said luminescent device.

3. luminescent device according to claim 2; Wherein, Said luminescent device can make the brightness from the brightness at 0 degree visual angle to 45 degree visual angle brightness reduce to be equal to or less than 30% of said 0 degree visual angle brightness, and can set chroma offset Δ uv value and satisfy relationship delta uv≤0.015.

4. luminescent device according to claim 3, wherein, the said second smooth reflecting interface utilizes metallic film to constitute, and this metallic film has the non-zero extinction coefficient and thickness is at least 5nm,

And the said the 3rd smooth reflecting interface and the said the 4th smooth reflecting interface all utilize refringence to constitute.

5. luminescent device according to claim 4, wherein, said luminescent device also has the 5th smooth reflecting interface, and it is used to regulate the flatness at said peak of the said spectral transmission curve of interference filter described in the said luminescent device.

6. luminescent device according to claim 5, wherein, at least one is divided into a plurality of smooth reflecting interfaces in the said second smooth reflecting interface, the said the 3rd smooth reflecting interface, the said the 4th smooth reflecting interface and the said the 5th smooth reflecting interface.

7. luminescent device according to claim 6 wherein, is suitable for equality n=0 and m=0.

8. luminescent device according to claim 1 wherein, forms duplexer thereby form said first electrode, said organic layer and said second electrode successively on substrate.

9. luminescent device according to claim 8 wherein is that transparent electrode layer, transparent insulating layer, resin bed, glassy layer or the air layer by thickness at least 1 μ m forms in the outside near the last light reflecting interface of said second electrode one side setting.

10. luminescent device according to claim 1 wherein, forms duplexer thereby form said second electrode, said organic layer and said first electrode successively on substrate.

11. luminescent device according to claim 10 wherein, is that transparent electrode layer, transparent insulating layer, resin bed, glassy layer or the air layer by thickness at least 1 μ m forms in the outside near the last light reflecting interface of said second electrode one side setting.

12. luminescent device according to claim 1, wherein, said organic layer is included in above part of said luminescent layer and following part.

13. a lighting apparatus, this lighting apparatus adopts a plurality of luminescent devices, and said a plurality of luminescent devices are used to launch the light with the plain color of differing from one another, and each luminescent device comprises:

Organic layer is clipped between first electrode and second electrode with as comprising the organic layer of launching monochromatic luminescent layer a position;

The first smooth reflecting interface is arranged near said first electrode, one side to make from penetrating this catoptrical interface near said second electrode, one side as the light of reflection from said luminescent layer emission; And

The second smooth reflecting interface, the 3rd smooth reflecting interface and the 4th smooth reflecting interface are arranged near the position that be separated from each other of said second electrode, one side on from said first electrode to the direction of said second electrode and set gradually,

Wherein, symbol L1 representes the optical distance between the luminescence center of the said first smooth reflecting interface and said luminescent layer;

Symbol L2 representes the optical distance between the said luminescence center and the said second smooth reflecting interface;

Symbol L3 representes the optical distance between said luminescence center and the said the 3rd smooth reflecting interface;

Symbol L4 representes the optical distance between said luminescence center and the said the 4th smooth reflecting interface;

The centre wavelength of the luminous spectrum of the said luminescent layer of sign of lambda 1 expression;

Symbol n, m, m ' and m " all represent integer;

Sign of lambda 11, λ 12, λ 13 and λ 14 all represent to interfere wavelength;

The long measure nanometer is as the unit of said wavelength X 1, λ 11, λ 12, λ 13 and λ 14;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said first smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said second smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said the 3rd smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said the 4th smooth reflecting interface reflex time;

Said optical distance L1, L2, L3 and L4 satisfy all expression formulas given below (1) and arrive (8):

be n>=0 wherein ... (1)

λ1-150＜λ11＜λ1+80 …(2)

λ1-80＜λ12＜λ1+80 …(6)

λ1-150＜λ13＜λ1+150 …(7)

λ1-150＜λ14＜λ1+150 …(8)。

14. a display device, this display device adopts a plurality of luminescent devices, and said a plurality of luminescent devices are used to launch the light with the plain color of differing from one another, and each luminescent device comprises:

Organic layer is clipped between first electrode and second electrode with as comprising the organic layer of launching monochromatic luminescent layer a position;

The first smooth reflecting interface is arranged near said first electrode, one side to make from penetrating this catoptrical interface near said second electrode, one side as the light of reflection from said luminescent layer emission; And

The second smooth reflecting interface, the 3rd smooth reflecting interface and the 4th smooth reflecting interface are arranged near the position that be separated from each other of said second electrode, one side on from said first electrode to the direction of said second electrode and set gradually,

Wherein, symbol L1 representes the optical distance between the luminescence center of the said first smooth reflecting interface and said luminescent layer;

Symbol L2 representes the optical distance between the said luminescence center and the said second smooth reflecting interface;

Symbol L3 representes the optical distance between said luminescence center and the said the 3rd smooth reflecting interface;

Symbol L4 representes the optical distance between said luminescence center and the said the 4th smooth reflecting interface;

The centre wavelength of the luminous spectrum of the said luminescent layer of sign of lambda 1 expression;

Symbol n, m, m ' and m " all represent integer;

Sign of lambda 11, λ 12, λ 13 and λ 14 all represent to interfere wavelength;

The long measure nanometer is as the unit of said wavelength X 1, λ 11, λ 12, λ 13 and λ 14;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said first smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said second smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said the 3rd smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said the 4th smooth reflecting interface reflex time;

Said optical distance L1, L2, L3 and L4 satisfy all expression formulas given below (1) and arrive (8):

be n>=0 wherein ... (1)

λ1-150＜λ11＜λ1+80 …(2)

λ1-80＜λ12＜λ1+80 …(6)

λ1-150＜λ13＜λ1+150 …(7)

λ1-150＜λ14＜λ1+150 …(8)。

15. display device according to claim 14, said display device also comprises:

Driving substrate wherein is provided with active device, and each said active device is used for the shows signal of each display pixel is fed to one of said luminescent device;

Hermetic sealing substrate is provided with in the face of said driving substrate;

Wherein, said luminescent device is arranged between said driving substrate and the said hermetic sealing substrate.

16. display device according to claim 15, wherein,

One of said driving substrate and said hermetic sealing substrate are at the substrate near said second electrode, one side of each said luminescent device; And

Colour filter is arranged on the said substrate near said second electrode, one side, as making from the transmittance penetrated near said second electrode, one side to the filter near the said substrate of said second electrode, one side.

17. a luminescent device comprises:

Organic layer is clipped between first electrode and second electrode with as comprising the organic layer of launching monochromatic luminescent layer a position;

The first smooth reflecting interface is arranged near said first electrode, one side to make from penetrating this catoptrical interface near said second electrode, one side as the light of reflection from said luminescent layer emission; And

The second smooth reflecting interface and the 3rd smooth reflecting interface are setting gradually in the position that is separated from each other on from said first electrode to the direction of said second electrode near said second electrode, one side,

Wherein, symbol L1 representes the optical distance between the luminescence center of the said first smooth reflecting interface and said luminescent layer;

Symbol L2 representes the optical distance between the said luminescence center and the said second smooth reflecting interface;

Symbol L3 representes the optical distance between said luminescence center and the said the 3rd smooth reflecting interface;

The centre wavelength of the luminous spectrum of the said luminescent layer of sign of lambda 1 expression;

Symbol n, m and m ' all represent integer;

Sign of lambda 11, λ 12 and λ 13 all represent to interfere wavelength;

The long measure nanometer is as the unit of said wavelength X 1, λ 11, λ 12 and λ 13;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said first smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said second smooth reflecting interface reflex time; And

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said the 3rd smooth reflecting interface reflex time;

Said optical distance L1, L2 and L3 satisfy all expression formulas given below (9) and arrive (14):

be n>=0 wherein ... (9)

λ1-150＜λ11＜λ1+80 …(10)

λ1-80＜λ12＜λ1+80 …(13)

λ1-150＜λ13＜λ1+150 …(14)。

18. luminescent device according to claim 17, wherein, almost smooth or gradient is each other about equally in the visible region at the peak of the spectral transmission curve of interference filter in the said luminescent device.

19. luminescent device according to claim 18; Wherein, Said luminescent device can make the brightness from the brightness at 0 degree visual angle to 45 degree visual angle brightness reduce to be equal to or less than 30% of said 0 degree visual angle brightness, and can set chroma offset Δ uv value and satisfy relationship delta uv≤0.015.

20. a lighting apparatus, this lighting apparatus adopts a plurality of luminescent devices, and said a plurality of luminescent devices are used to launch the light with the plain color of differing from one another, and each luminescent device comprises:

Organic layer is clipped between first electrode and second electrode with as comprising the organic layer of launching monochromatic luminescent layer a position;

The first smooth reflecting interface is arranged near said first electrode, one side to make from penetrating this catoptrical interface near said second electrode, one side as the light of reflection from said luminescent layer emission; And

The second smooth reflecting interface and the 3rd smooth reflecting interface are setting gradually in the position that is separated from each other on from said first electrode to the direction of said second electrode near said second electrode, one side,

Wherein, symbol L1 representes the optical distance between the luminescence center of the said first smooth reflecting interface and said luminescent layer;

Symbol L2 representes the optical distance between the said luminescence center and the said second smooth reflecting interface;

Symbol L3 representes the optical distance between said luminescence center and the said the 3rd smooth reflecting interface;

The centre wavelength of the luminous spectrum of the said luminescent layer of sign of lambda 1 expression;

Symbol n, m and m ' all represent integer;

Sign of lambda 11, λ 12 and λ 13 all represent to interfere wavelength;

The long measure nanometer is as the unit of said wavelength X 1, λ 11, λ 12 and λ 13;

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said first smooth reflecting interface reflex time;

The light that each wavelength is worked as in symbol expression is by the observed phase change of the said second smooth reflecting interface reflex time; And

The light that each wavelength is worked as in symbol

expression is by the observed phase change of the said the 3rd smooth reflecting interface reflex time;

Said optical distance L1, L2 and L3 satisfy all expression formulas given below (9) and arrive (14):

be n>=0 wherein ... (9)

λ1-150＜λ11＜λ1+80 …(10)

λ1-80＜λ12＜λ1+80 …(13)

λ1-150＜λ13＜λ1+150 …(14)。

21. a display device, this display device adopts a plurality of luminescent devices, and said a plurality of luminescent devices are used to launch the light with the plain color of differing from one another, and each luminescent device comprises:

Organic layer is clipped between first electrode and second electrode with as comprising the organic layer of launching monochromatic luminescent layer a position;

The first smooth reflecting interface is arranged near said first electrode, one side to make from penetrating this catoptrical interface near said second electrode, one side as the light of reflection from said luminescent layer emission; And

The second smooth reflecting interface and the 3rd smooth reflecting interface are setting gradually in the position that is separated from each other on from said first electrode to the direction of said second electrode near said second electrode, one side,

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